Various bleaches have long been employed in numerous cleaning applications including the washing and prewashing of fabrics as well as in other applications such as hard surface cleaning. In these applications, the bleaching agent oxidizes various stains or soils on fabrics, textiles and hard surfaces.
Peroxygen bleaching compounds such as hydrogen peroxide, sodium percarbonate and sodium perborate have been found useful in dry bleach formulations because of their oxidizing power.
It has also been found that certain organic compounds, including activators such as tetraacetylethylenediamine, can be added to perborate bleaches for improved bleaching performance because of in situ formation of peracetic acid.
Cleaning compositions for fabrics, textiles and other materials including hard surfaces have also been developed which employ various enzymes for removing certain stains or soils. Protease enzymes have been found useful for hydrolyzing protein-based stains particularly in the cleaning of fabrics. Amylase enzymes have been found useful against carbohydrate-based stains resulting, for example, from foods. Lipase enzymes have also been found useful for hydrolyzing fat-based stains in a prewash or presoak mode.
In connection with the use of enzymes in cleaning or detergent compositions, European Patent Application, Publication, No. 0 130 064, (1985), applied for by Novo Industry A/S, related to improvements in enzymatic additives for use with detergents in washing applications. That publication discussed the use of lipase enzymes for achieving substantially improved lipolytic cleaning efficiency, over a broad range of wash temperatures including relatively low temperatures below 60.degree. C. This reference further disclosed the use of enzymes, including lipases, for direct interaction with stains or soils as a means of at least partially dissolving or loosening such fat-based stains.
U.S. Pat. No. 3,974,082, issued Aug. 10, 1976 to Weyn, disclosed a bleaching composition and method of use in which an acyl-alkyl ester was used with an esterase or lipase enzyme in an aqueous medium. However, nothing in the prior art disclosed or taught that proteases can be used in combination with a source of hydrogen peroxide and selected ester substrates to produce peracid in an aqueous medium. In any event, there has been found to remain a need for improved bleaching or activated oxidant systems capable of enhanced performance in aqueous solution under high or low temperature wash conditions.